The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingMonitor drive pattern
Test monitor drive pattern for ect
Caution:
Perform this drive pattern on a level surface and
strictly observe the posted speed limits and traffic
laws while driving.
Hint:
Performing this drive pattern is one method to simulate
the ect's malfunction detection conditions.
The dtcs may ...
Reassembly
V
Attach the 7 outside moulding retainers to install the
extension.
Install front bumper extension rh (for wide
body)
Hint:
Use the same procedures described for the lh side.
Install front bumper hole cover lh (w/o fog
light)
Install the bumper hole cover with ...
Removal
Drain engine coolant (see page co-6)
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove air cleaner cap (see page es-41 ...